前者強(qiáng)調(diào)過去某個(gè)時(shí)間發(fā)生的動(dòng)作,一般有動(dòng)作發(fā)生時(shí)的具體時(shí)間.句式是主語加動(dòng)詞的過去式.后者表示“過去的過去,強(qiáng)調(diào)在過去某個(gè)時(shí)間前已經(jīng)完成的動(dòng)作,常跟“表示一段時(shí)間”的詞for等連用.句式：had后跟動(dòng)詞的過去分詞.例如：He ate his dinner at 9 o'clock last night.（一般過去時(shí)態(tài),他昨晚9點(diǎn)才吃晚飯）He had already been there for ten years before he left Shanghai last year.（過去完成時(shí)態(tài),他去年離開上海前已經(jīng)在那里住了10年了）